A concerted study of the cancer cell and its interaction with the host in a coordinated and cooperative effort by four major groups of investigators is being carried out at the Roswell Park Memorial Institute. Studies are being made on cell interactions and membrane biophysics as these relate to metastasis, invasion, drug delivery, carcinogenesis, cancer/embryonic cell interactions, macrophage movement, etc.; receptor sites, cell-mediated immunity, immunochemistry and antigenic structure; cytogenetic and nuclear membrane ultrastructure and biochemistry; photoactivation of dyes in cancer therapy, radiosensitizing drugs and therapeutic uses of hyperthermia. Whenever possible, studies will be made of the same cells and cell lines so that the study efforts will be coordinated from a common base line. This is in contrast to the situation which so frequently exists in which different cells are studied by different groups so that final direct correlations are impossible. This coordination and cooperation will include sharing of the facilities and equipment including animal, washing, cell culture, electron microscope, and radiation facilities.